Road safety campaigners have condemned Haringey’s plans for a blanket 20mph limit on residential roads after figures revealed that average speeds in neighbouring Islington have not decreased since a similar restriction there.

Average speeds on nearly 100 roads in Islington have remained the same since the controversial limit was implemented last year, according to data released under the Freedom of Information Act.

The discovery prompted Highgate data researcher Simon Briscoe to brand Haringey Council’s proposals for a 20mph limit on side roads as “pointless”.

The vice-chairman of Highgate Neighbourhood Forum, of Highgate Village, said: “It’s extremely difficult to speak out against this because it makes politicians feel very warm and happy to introduce this policy. But I would say that at the moment there is absolutely no evidence that the limit is worth bothering with.”

Mr Briscoe, who obtained the figures, added: “The majority of road accidents occur on major roads like Archway Road, Highgate Hill, North Road and North Hill. The reality is down the side roads there’s no-one going over 20mph in any case.”

Since the blanket 20mph restriction was introduced in Islington, average speeds on 156 of 158 roads surveyed by the council last autumn were above the limit.

While average speeds on 39 roads decreased by more than 2mph since 2011 and 2012, they increased at 24 locations. In 95 roads, speeds did not change by more than 2mph.

In Camden, it is too early to reveal how speeds have changed since the council introduced a borough-wide 20mph limit in December last year.

However, Cllr Phil Jones, Camden’s cabinet member for transport, said decreasing speeds is not the aim. “We would not be expecting to see a big reduction in speeds,” he said. “This is a long-term process. I would say introducing a 20mph limit is not the end of it, it’s the beginning.

“Once you’ve introduced it, you then look at where you’ve still got problems and what you can do about it, with traffic measures or pressing police to take enforcement action.”

Journalist Charley Allan, 41, who campaigns for a safer pedestrian crossing near Highgate Primary School in North Hill, is unconvinced by Haringey’s proposals.

“A blanket limit could cause a lot of problems,” the father-of-two, of Shepherd’s Hill, said. “Anything that gives more attention to road safety is good but nobody speaks up for pedestrians.”

A Haringey Council spokesman said: “We consulted widely on the idea of a 20mph limit in Haringey and more than 4,500 people responded with overwhelming support for it to be introduced in residential roads and town centres.

“We are now drawing up detailed plans to introduce a 20mph limit to most of the borough and we will be talking again to road users, residents’ groups, and cycling and disability groups to ensure we have an appropriate mixture of speed limits across the borough, with the vast majority of our roads being 20mph.”

A controversial proposal to build an 11-storey residential tower in the heart of West Hampstead will be considered by Camden Council tonight – as the lone Labour councillor vocally opposing the plans is criticised by colleagues and branded “misguided”.